Tractor-trailer trucks are designed to be connected and disconnected. The trailer air brakes are powered and controlled from the tractor through two pneumatic lines—one line supplies air at full system pressure to power the trailer brakes, and the other supplies a pneumatic control signal of varying pressure to indicate when the brakes should be applied or released. The standard connection for these lines between the tractor and trailer is called a gladhand. When the trailer is disconnected from the tractor, the gladhands are generally exposed to the environment, and thus allow water, debris and insects into the system. Water and debris in the system can impact the brake control valves and may even cause them to malfunction.
Prior solutions to this problem include U.S. Pat. No. 6,358,291 directed to a dual desiccant bed device for capturing incidental water entering the system and subsequently releasing it slowly into dried air from the tractor. U.S. Pat. No. 5,762,094 is directed to a drain mechanism incorporated into the brake relay valve, however, such a mechanism is generally incompatible with anti-lock brake systems. As such, there exists a need to provide a mechanism for capturing and venting any water that is introduced into the trailer air brake system while the gladhands are open.